1. Field of the Invention
The present invention relates to an ejector and a manufacturing method thereof.
2. Description of Related Art
In a case of a previously known ejector, a fluid is drawn from a fluid suction opening by a vacuum force created by high velocity fluid discharged from a nozzle, which depressurizes and expands the high velocity fluid. In this type of ejector, the discharged fluid, which is discharged from the nozzle, and the drawn fluid, which is drawn through the fluid suction opening, are mixed to form the fluid mixture. Then, the kinetic energy of the fluid mixture is converted into the pressure energy at a pressurizing portion (a diffuser portion), so that the pressure of the fluid mixture is increased.
For example, Japanese Unexamined Patent Publication No. 2005-308380 (corresponding to US 2005/0178150A1 and US 2005/0268644A1) discloses an ejector refrigeration cycle, which uses an ejector as a refrigerant depressurizing means for depressurizing the pressure of the refrigerant. In this ejector refrigeration cycle, a drive force of a compressor is reduced by the pressurizing action of the ejector, so that a coefficient of performance (COP) of the refrigeration cycle is improved.
Furthermore, in Japanese Unexamined Patent Publication No. 2007-057222 (US 2008/0264097A1), the ejector refrigeration cycle is applied to a vehicle refrigeration cycle system. In this ejector refrigeration cycle, the ejector and another constituent device (e.g., an evaporator) of the refrigeration cycle are integrated together to reduce an entire size of the ejector refrigeration cycle and to improve an installability of the ejector refrigeration cycle.
In the ejector refrigeration cycle, for example, a flow quantity of the circulated refrigerant, which is circuited in the ejector refrigeration cycle, is changed according to a required performance of the refrigeration cycle. Therefore, it is also required to appropriately change the specification of the ejector by changing the sizes of, for example, the nozzle and the diffuser portion of the ejector according to the required performance of the refrigeration cycle to implement the above-described improvement in the coefficient of performance (COP).
Furthermore, in general, the constituent devices of the ejector refrigeration cycle, such as the compressor, the radiator, the ejector and the evaporator, are separately constructed and are connected together through refrigerant pipes or through direct connection.
Therefore, in the case where the ejector refrigeration cycle is applied to different refrigeration cycle systems, which have different required performances, when the specification of the ejector is changed to change the outer sizes of the ejector and the shapes of the connections of the ejector connected to the other constituent devices of the refrigeration cycle, the installability of the ejector relative to the other constituent devices (external devices) of the refrigeration cycle may possibly be deteriorated.
Particularly, in the case where the ejector and the other constituent device (external device) of the ejector refrigeration cycle are integrated together like in the case of Japanese Unexamined Patent Publication No. 2007-057222 (US 2008/0264097A1), the ejector and the other constituent device cannot be integrated together when the outer sizes of the ejector and the shapes of the connections of the ejector are changed due to the existence of the installation space limitations of the ejector.
However, it is difficult to change the specification of the ejector without changing the outer sizes of the ejector and the shapes of the connections of the ejector due to the requirements of the high precision at the time of manufacturing the nozzle or the diffuser portion of the ejector.
Also, in the case where the ejector is connected to the other constituent devices (the external devices) of the ejector refrigeration cycle, when the connections are made by heating the connections to the high temperature like in the case of the brazing, the thermal deformation may possibly occur to the corresponding parts of the ejector. In view of this, it is conceivable to use mechanical fastening, such as fastening using a union and a nut, which are tightened together. However, in the case of the mechanical fastening, the corresponding parts of the ejector may possibly be deformed by, for example, the torsional stress applied at the time of tightening the union and the nut together.
When such a deformation occurs in the corresponding parts of the ejector, the performance (the pressurizing performance, i.e., the pressure increasing performance) of the ejector may possibly be deteriorated.